Air Conditioner Troubleshooting
 

Can anyone point me in the direction of an air conditioner troubleshooting guide? I have an '05 JCW with automatic climate control and approximately 146,000 miles. The air conditioner has always worked fine until last Friday. I was on the interstate going about 70 mph and the control set on 68 F. Within a few seconds hot air started blowing out. The ambient temp was about 90 F. I turned the control to LO and got a few more seconds of cold air and then nothing but hot. The A/C light does light up.

I searched the forum and found a lot of possibilities and things to try but I am trying to approach it systematically so I don't overlook anything.

Thanks in advance.

start with checking the freon, it's were I'd start but if you don't have a gauge you need to get one, pretty cheap now a days.

Cheapest way to check is get a can of R134a and a gauge. But given your failure scenario, it's more likely the compressor or some other component went out. A leak should have resulted in slowly degrading performance.
My AC died and I replaced the compressor and had a shop drain and refill.
I'm a DIY guy, but when it comes to AC, equipment and experience give the shop an edge. Wouldn't pay shop rates to swap the compressor/drier, but probably worth it for diagnostic if the failure isn't clear.
Lots of old posts under my name in dealing with my AC failure and replacement.

Check your fuses first and swap relays with the other matching ones in the relay panel. Is your compressor cycling on and off? If not, try pulling the compressor relay and jumping the pins (#87 and #30 I think) with the car running. That will tell you if your compressor is still functioning. If there is a pressure switch or something stopping it, bypassing the relay will help to troubleshoot. If it still doesn't cycle on when you bypass the relay, check for resistance between pins 87 and 30 to see if your compressor clutch coil has shorted out.

Thanks.
Got a gauge, static high and low side both 105; both 115 with A/C on LO.
Fuse is good. Swapped relays, compressor not cycling.Jumped pins, still not cycling. Checked resistance, it was off the scale, infinite resistance.
Looks like it's the clutch coil.

I did my clutch coil a while ago. it was pretty easy to change. Just an awkward spot to work in.

Thanks for the feedback.
Did you remove lower engine mount and use a load ratchet strap to move engine back? (I saw this referenced in a and I'm trying to learn more about it)

That's how I did mine.

I sure did. gives you a good amount of room to work. you won't be able to get the top bolt unless you pull the engine back OR pull the radiator off.

:thumbsup:Thanks for everyone's feedback.:thumbsup:
Cooler weather came so I put this project on hold. I tackled it a couple of weeks ago and it wasn't too bad. I did use the ratchet strap to pull the engine back.
Now that the hot weather is here, I've got cold air again.

You might be able to find an answer to your question in our mini tech forums or you can post this question directly there too and usually a technician will respond with an answer for you.

-Luccia

I think he already replaced his Compressor Clutch assembly from his previous post, which in turn fixed his problem. :thumbsup:

Ah! Thank you for that. :thumbsup: